Assessing social dynamics and HIV outcomes to inform interventions with transgender women living with HIV Project Summary: Transgender (trans) women across the globe experience dramatic HIV disparities with an estimated global HIV prevalence of 19%. There is a growing literature suggesting that trans women living with HIV experience sub-optimal care and treatment outcomes compared to other populations, but very few examples of holistic, comprehensive interventions to promote positive HIV outcomes and emotional wellbeing. The anthropological concept of syndemics has been used extensively to frame and measure HIV vulnerability and outcomes among trans women. While a key component of syndemics is recognition of the context of negative social and physical conditions that increase vulnerability, there are still major gaps in understanding of the pathways of influence from these multiple, overlapping conditions, especially stigma, to behavioral and biological HIV outcomes, including retention in care, adherence to anti-retroviral therapy and viral suppression. In the parent study of the proposed supplement (MH110158: Kerrigan, PI), we are assessing how stigma and social cohesion influence HIV outcomes among a cohort of 200 cisgender women sex workers living with HIV in Santo Domingo. While social cohesion within the sex worker community has been a central element of community-based responses to HIV and is significantly associated with protective behaviors among cisgender women sex workers, these relationships are less explored among trans women sex workers. Moreover, in the Dominican context, processes of social cohesion and mobilization are more nascent in the transgender community and challenges exist to establishing trust and mutual support. As an example, our team recently adapted a multi-level intervention, called Abriendo Puertas (Opening Doors), originally designed for cisgender women sex workers living with HIV, for trans women sex workers living with HIV (n=30). While the individual level intervention component was easily adapted and implemented with trans women, the peer and community mobilization components were more difficult due to lack of trust and social cohesion, highlighting the need for greater understanding of social and community dynamics in this population. The purpose of the proposed supplement is to improve understanding of how stigma and cohesion impact HIV outcomes in transgender women sex workers living with HIV in the DR. For Aim 1 we will conduct qualitative in-depth interviews with trans women sex workers living with HIV (n=20) to explore experiences with and discourses around stigma (related to HIV, gender, and sex work), social networks, and social cohesion. In these interviews, we will also pilot the measures of sex work stigma that we are developing in the parent study to their salience with this population. For Aim 2, we will conduct quantitative surveys with trans women sex workers living with HIV in three cities in the Dominican Republic (n=100) to assess the association between stigma, cohesion and behavioral and biological HIV outcomes.